A. Field of the Invention
The present invention relates to the field of modular electronic devices, and more particularly to a locking device for retaining computer peripheral modules within a computer system housing.
B. Art Background
A personal computer system is typically made up of a number of components. In addition to the central processing unit (CPU), there are peripheral units such as video displays, memory units, disk drives, tape drives, printers, and others. Often, these units are incorporated into a housing that also contains the CPU. The peripheral units may be contained within modules. These modules are connected to and can be removed from the housing, allowing the user of the computer system to customize its features.
The modules are placed within the housing in a manner similar to drawers. The modules are supported by rails and slide into the housing on the rails. Typically, modules are in the shape of a rectangular box, although other shapes can be used. When electrical power is turned on, the modules are automatically powered up.
The peripheral modules must be electrically and physically connected to the housing which holds the computer system. An electrical connection is necessary because the CPU must be able to communicate with the peripheral devices and pass data to and from them. Also, the peripheral unit needs to be connected to the computer system's power supply and the communications bus. The electrical connection is most often made by means of a pair of connectors. One connector is mounted on the housing, and the other is mounted on the module. As the module is placed within the housing, the connectors are aligned so that the electrical connection is automatically made between the peripheral device and the rest of the computer system.
It has been found that it is undesirable to disconnect the modules from the housing while the computer system is turned on and electrical power is supported to the modules. If the modules are disconnected from the power supply, electrical noise spikes can occur across the connector pins. These noise spikes are undesirable because they may lead to spurious data signals and in some instances may even damage the peripheral device. It is therefore desirable to provide a means for retaining the module inside the system housing while power is supplied to the module.
In the prior art, methods are known which hold the peripheral modules in the housing. For example, locking screws may be placed on the front panel of the module. When the module is placed within the housing, the screws are tightened thereby holding the module in place. However, this method has a disadvantage in that the screws can be unfastened at any time. Thus, a user may possibly release the locking screw and remove the module from the housing when power is connected to the computer system. The prior art does not provide a method for insuring that the modules remain within the housing whenever the computer system is powered up.